1. Field of Invention
This invention relates to photolithographically-formed microelectronic interconnect structure.
2. Description of Related Art
Design and fabrication of integrated circuits (ICs) have made rapid advances which require similar advances in the design and fabrication of chip-to-substrate electrical interconnect structures, and of high density substrates. For example, millions of transistors can be fabricated onto a 10×10 mm die with input/output (I/O) pad densities reaching about 1600/cm2. This fabrication will eventually reach a billion transistors or more on a 10×10 mm die, and, in response, the die-to-substrate I/O pad density will eventually reach about 6000/cm2 or more.